It is necessary to collect information about processing performance of a network system to monitor or manage a data communication network system, and, to collect this information, protocol latency in environment of encrypted communication is measured.
For example, Patent Document 1 discloses a conventional method of measuring protocol latency. According to this method, to measure protocol latency deriving from encryption processing in a kernel layer (i.e. communication protocol stack) in a communication terminal, the communication terminal encrypts in the application layer the same data as unprocessed data to which encryption processing is not yet applied, and stores the signature acquired upon encryption. Then, the unprocessed data is encrypted in the kernel layer, and the signature acquired upon encryption and the stored signature are compared to guarantee that data is the same before and after encryption in the kernel layer. Next, protocol latency is measured for the data that is guaranteed as the same data.
Patent Document 1: U.S. Pat. No. 6,363,477 Specification